/*
 * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sun.org.apache.xpath.internal.axes;

import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.objects.XObject;
import com.sun.org.apache.xpath.internal.patterns.NodeTest;

/**
 * This class defines a simplified type of union iterator that only
 * tests along the child axes.  If the conditions are right, it is
 * much faster than using a UnionPathIterator.
 */
public class UnionChildIterator extends ChildTestIterator {
    static final long serialVersionUID = 3500298482193003495L;
    /**
     * Even though these may hold full LocPathIterators, this array does
     * not have to be cloned, since only the node test and predicate
     * portion are used, and these only need static information.  However,
     * also note that index predicates can not be used!
     */
    private PredicatedNodeTest[] m_nodeTests = null;

    /**
     * Constructor for UnionChildIterator
     */
    public UnionChildIterator() {
        super(null);
    }

    /**
     * Add a node test to the union list.
     *
     * @param test reference to a NodeTest, which will be added
     *             directly to the list of node tests (in other words, it will
     *             not be cloned).  The parent of this test will be set to
     *             this object.
     */
    public void addNodeTest(PredicatedNodeTest test) {

        // Increase array size by only 1 at a time.  Fix this
        // if it looks to be a problem.
        if (null == m_nodeTests) {
            m_nodeTests = new PredicatedNodeTest[1];
            m_nodeTests[0] = test;
        } else {
            PredicatedNodeTest[] tests = m_nodeTests;
            int len = m_nodeTests.length;

            m_nodeTests = new PredicatedNodeTest[len + 1];

            System.arraycopy(tests, 0, m_nodeTests, 0, len);

            m_nodeTests[len] = test;
        }
        test.exprSetParent(this);
    }

    /**
     * This function is used to fixup variables from QNames to stack frame
     * indexes at stylesheet build time.
     *
     * @param vars List of QNames that correspond to variables.  This list
     *             should be searched backwards for the first qualified name that
     *             corresponds to the variable reference qname.  The position of the
     *             QName in the vector from the start of the vector will be its position
     *             in the stack frame (but variables above the globalsTop value will need
     *             to be offset to the current stack frame).
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize) {
        super.fixupVariables(vars, globalsSize);
        if (m_nodeTests != null) {
            for (int i = 0; i < m_nodeTests.length; i++) {
                m_nodeTests[i].fixupVariables(vars, globalsSize);
            }
        }
    }

    /**
     * Test whether a specified node is visible in the logical view of a
     * TreeWalker or NodeIterator. This function will be called by the
     * implementation of TreeWalker and NodeIterator; it is not intended to
     * be called directly from user code.
     *
     * @param n The node to check to see if it passes the filter or not.
     * @return a constant to determine whether the node is accepted,
     * rejected, or skipped, as defined  above .
     */
    public short acceptNode(int n) {
        XPathContext xctxt = getXPathContext();
        try {
            xctxt.pushCurrentNode(n);
            for (int i = 0; i < m_nodeTests.length; i++) {
                PredicatedNodeTest pnt = m_nodeTests[i];
                XObject score = pnt.execute(xctxt, n);
                if (score != NodeTest.SCORE_NONE) {
                    // Note that we are assuming there are no positional predicates!
                    if (pnt.getPredicateCount() > 0) {
                        if (pnt.executePredicates(n, xctxt))
                            return DTMIterator.FILTER_ACCEPT;
                    } else
                        return DTMIterator.FILTER_ACCEPT;

                }
            }
        } catch (javax.xml.transform.TransformerException se) {

            // TODO: Fix this.
            throw new RuntimeException(se.getMessage());
        } finally {
            xctxt.popCurrentNode();
        }
        return DTMIterator.FILTER_SKIP;
    }

}
